Pyridyl azides and derivatives thereof

ABSTRACT

The invention is a group of compounds of the formula   WHEREIN X is halogen; Y is nitrile, carboxamide, carboxyl, ester or trihalomethane; m is 1-4; n is 0-4; p is 0-2; and m + n + p is 2-5. The compounds, which generally may be prepared by introducing the azide moiety by exchange with a ring halogen, have been found to be useful as high energy compounds, such as detonators.

United States Patent [1 1 Pannell May 13, 1975 PYRIDYL AZIDES AND DERIVATIVES THEREOF [75] Inventor:

Calvin E. Pannell, Walnut Creek, Calif.

{73] Assignee: The Dow Chemical Company,

Midland, Mich.

221 Filed: July 25,1973

21 Appl. No.: 382,432

Related US. Application Data [62] Division of Ser. No. 230,975, March I, 1972, Pat.

[52] US. Cl 260/295 R; I49/I09; 260/2949; 260/295 AM; 260/2955 A; 260/2955 R;

[SI] Int. Cl C07d 31/34 [58] Field of Search 260/349, 295 R, 295 A, 260/2955 R, 295.5 A

[56] References Cited UNITED STATES PATENTS 2/l944 Kaase et al. ..i 260/349 X Il/l973 Pannell 260/2949 OTHER PUBLICATIONS Chemical Abstracts, vol. 43, col. 8366a (I949). Chemical Abstracts, vol. 49, col. 6964f( I955).

Chemical Abstracts, vol. 50, col. 9330h (I956). Chemical Abstracts, vol. 53, col. 952d 1959) Primary ExaminerJohn D. Randolph Attorney, Agent, or FirmJ. Roger Lochhead [57] ABSTRACT The invention is a group of compounds of the formula wherein X is halogen; Y is nitrile, carboxamide, carboxyl, ester or trihalomethane; m is 1-4; n is 0-4; p is 0-2; and m n p is 2-5. The compounds, which generally may be prepared by introducing the azide moiety by exchange with a ring halogen, have been found to be useful as high energy compounds, such as detonators.

2 Claims, No Drawings SUMMARY OF THE INVENTION The invention is a group of compounds of the formula wherein each X is, independently, Cl, Br, I or F; Y is CCl CF CN,

(each R independently being H, aryl (phenyl or naphthyl) or an alkyl group of up to about 18 carbon atoms), COOH or COOR' (R' being the residue of an esterifiable organic hydroxy compound such as alkyl, aryl, alkaryl and aralkyl esters with up to 18 carhens in the alkyl portion); m is l to 4; n is 0 to 4; p is Oto 2; and thesum ofm+n+pisfrom 2to 5.

The compounds of this invention may be prepared from known starting materials by exchanging an active ring-substituted halogen for an azide. They may also be prepared by diazotization of a ring-substituted amine group, with subsequent exchange of said azo group for an azide group.

The compounds have been found to be useful as high energy compounds, such as detonators, propellants, and the like.

Those compounds in the above formula wherein m is 3 to 4, Y is CN, p is l to 2 and n is 0 are preferred.

DETAILED DESCRIPTION OF THE INVENTION The compounds of the invention are prepared by replacing one or more ring-substituted halogens with an azide. Metal azides, such as NaN or KN are suitable for said replacement.

The reaction conditions depend upon the reactivity of the particular pyridine compound in question. A reactive halogen compound, such as 2-cyano-3,4,5,6- tetrachloropyridine, will react readily with room temperature, overnight stirring of u methanolic solution of the reactants. Less reactive materials will either require longer reaction times, higher reaction temperatures or the use of a more favorable solvent, such as dimethylformamide. No effort should be made to force the reaction by use of severe conditions until trial microexperiments furnish definite knowledge regarding the stability of the resulting azide reaction products. Generally speaking, a direct relationship exists concerning instability and the number of azide groups per molecule, the monoazide compounds usually being the most stable.

The degree of substitution is dependent upon the relative quantity of metal azide used and whether the pyridine compound contains activating groups or easily replaceable halogen, especially a halogen in the two position.

The normal reaction course involves a stepwise reaction sequence, the four or para position generally being the most reactive, followed by the two and six positions. A different reaction mechanism occurs once a two or six position is substituted with an azide group. The overall sequence is generally as follows? III It is to be noted that compound Ill is in equilibrium with the adjacent heterocyclic nitrogen and forming a tetrazole. This azide-tetrazole transformation profoundly alters the reactivity of the remaining ring halogens with the six-position chlorine atom reacting as soon as compound [11 forms. The final result is that compound "I is generally a transitory intermediate.

Trichloromethyl or trifluoromethyl-substituted pyridyl azides, with or without halogen substituents, may be prepared from, for instance, 3-amino 3,5,6'dichloro-2- trichloromethylpyridine (U.S. Pat. No. 3,224,950); 2, 3,4-trich1oro-2-trichloromethy1pyridine (U.S. Pat. No. 3,256,167); o-chloro-2-trichloromethylpyridine (U.S. Pat. No. 3,418,323); and, halo, trifluoromethylpyridines (U.S. Pat. No. 3,609,158). Other trihalocontaining pyridines are taught in Chemistry ofPyridine Derivatives by Edwin Klingberg (lnterscience, 196]), specifically in Part 2, pp. 398-99.

Pyridyl azides with cyano substituents may be pre pared, for instance, from 4-NR (R is H or a1ky1)-2- cyano-3,5,6-trichloropyridine (U.S. Pat. No. 3,285,925); haloand cyano-substituted pyridines are made according to the process taught in US. Pat. No. 3,420,833; polybromo, cyanopyridines (U.S. Pat. No. 3,595,868); chlorocyanopyridines (U.S. Pat. No. 3,591,597); and, polychloro, monoor dicyanopyridines (U.S. Pat. No. 3,325,503).

COOH, COOR or CONR -substituted pyridyl azides may be prepared from, for instance, 4-NR' (R' is H or alkyl)2-COOH or CONR -3,5,6- trichloropyridines (U.S. Pat. No. 3,285,925); 3,6- dichloropicolinic acid (U.S. Pat. No. 3,317,549); or Klingsberg, Part 3, pp. 303-07.

Polyhalopyridines are taught, for instance, in US Pat. Nos. 3,303,197, 3,557,124, 3,186,994, 3,555,032 and 3,595,868; Belgian Pat. No. 660,873; and Klingsberg, Part 2, pp. 385-91. Haloaminopyridines are also taught in US. Pat. Nos. 3,224,950 and 3,285,925, and Klingsberg, Part 2, pp. 38591 and Part 3, pp. 836.

As a general procedure, the pyridine and a metal azide are stirred into solution in a solvent, such as dimethylformamide, and the solution optionally heated. When the replacement reaction is complete, the resulting pyridyl azide may be precipitated in water, ex tracted with ether, the solvent evaporated, and the azide recrystallized from a solvent, such as sec-buty1 alcohol.

It is to be noted that the resulting compounds may well be shock and/or friction sensitive. Extreme care should also be taken when heating, particularly as the number of azide groups increases.

Care should be further exercised when elemental analyses are being conducted. Microanalysis can be successfully accomplished providing the microanalyst has sufficient background regarding the successful combustion of high energy compounds. Adequate shielding of the combustion tube is essential.

The utility of these materials in high energy fuels and detonators is based upon their fuel value as well as direct and reproducible energetics of decomposition. These azides are compatible with hydrazine and the UDMH mixture, thus permitting one to modify the N O -hydrazines liquid propellant system. The impact sensitivity of the polyazide compounds coupled with the completely non-metallic decomposition gases results in reduced fouling and barrel corrosion. Solid propellant formulations, especially for flare applications, are preferred utilities.

SPECIFIC EMBODIMENTS EXAMPLE 1 Tetraazidopicolinonitrile 24.2 gm. (0.1 mole) of tetrachloropicolinonitrile was mixed with 32.5 gm. (0.5 mole) of NaN the entire mass then being slurried with 100-150 ml. of dimethylformamide (DMF). The material dissolved upon heating to C., whereupon it was stirred at that temperature for 18 hours.

The solution, which contained suspended NaCl, was poured into ice water and the solids were filtered and washed with water several times. A small quantity was recrystallized from sec-buty1 alcohol for determination of melting point. Caution was exercised due to the expectation of impact and friction sensitivity.

Melting point was found to be 99.5103.5 C., and analysis showed the sample to be tetraazidopicolinonitrile.

EXAMPLES 2-13 In a manner similar to Example 1, the following pyridyl azide compounds were prepared by reacting the proper pyridine with NaN Starting material and conditions are listed in the following Table:

Reaction Reaction Ex. Starting Material Solvent and Grams Time Temp. Pyridyl Azidc No. and Weight Used Amount NaH (Hours) (C.) Recovered 2. 0.05 moles of 150 m1. DMF (0.264 2 90 3,5-dichloro-2,4,6- pentachloropyridinc moles) triazidopyridine 3. 0.2 moles of 375 m1. DMF (0.2 3 4-azido4etrachloropenlachloropyridinc moles) pyridine 4. 1.12 gm. of tetra- 100 ml. DMF 1.12 24 65 3 azido-trichloropic0- chluropicolinic acid linic acid 5. 8.4 gm. of 246- 50 ml. DMF 1.63 36 25 mole 4azidotribromopyridine 2,6-dibromopyridine 25 mole 4,6diazido Lbromopyridinc 6 18.2 gm. of 2,3,6- ml. DMF 6.5 72 60 2,6-diazido 3-ch1orotrichloropyridinc pyridinc 7. 304 gm. of 2,3, 450 ml. MoOH 9.1 72 60 4azido-2,3,5-tri 4,5-tetrachloropyridine chloropyridinc 8. 5 gm. of 2,4,6-tri 50 ml. DMF 1.63 36 25 4-azido-2,6difluorof1uoro-3,5-di- 3,5-dichloropyridinc chloropyridinc 9. 70.5 gm. of tetra- 500 m1. 18.8 18 2S 4-azido-2-cyanochloro-2-cyano- MeOH trichloropyridine pyridine 10. 12.1 gm. of tetra- 50 ml. DMF 3.25 18 2-azido-4cyanochloro-4 cyanopyridine trichloropyridinc -Continued Reaction Reaction Ex. Starting Material Solvent and Grams Time Temp. Pyridyl Azide No. and Weight Used Amount NaH (Hours) (C.) Recovered l I. l2.l gm. of tetra- 50 ml. DMF 33 I8 80 6-azido-3-cyanochloro-3-cyanotrichloropyridine pyridine l2. 23.8 gm. of tetra 250 ml. DMF 9.69 24 25 4,6-diazido-3,5-dichlorochloro-Z-trichloro- Z-trichloromethylpyridine methylpyridine l3. 0.02 moles of 2,6- I50 ml. DMF (0.022 24 25 80 mole 4-azido3,5-

bis(trichloromethyl)- moles) dichloroand 20 mole trichloropyridine 4,5-diazido-3-chloro- 2,6-bis(trichloromethyl)- pyridine EXAMPLE l4 3 n A brass chamber I0 mm. in diameter, constricted at one end to 7.62 mm.) is charged with Belgian Ball" propellant. At the base of the mm. chamber, a quantity of Z-cyanotetraazidopyridine is affixed in a manner that impacting energy will be transmitted to the azide compound. lmpact is accomplished by use of a hardened steel impactor and smooth discharge of the Ball Powder" results.

The detonator could similarly be discharged by utilizing an electric spark.

1 claim: 1. A compound of the formula 2. 4-Azid0-trichloropic0]inic acid. 

1. A COMPOUND OF THE FORMULA
 2. 4-Azido-trichloropicolinic acid. 